Design, Architecture, Gardens, Southern California Living

The Dry Garden: What late-season rains and a prediction for a cool June mean for gardeners

May 18, 2011 | 9:13
am

Our Friday sustainable gardening column posted early this week because of the storm:

After an ample rain year, May showers are a mixed blessing in the Southern California garden. On the upside, it’s cool outside; damp soil yields easily to the weed fork, and late rain keeps the window open to sow more seeds and transplant seedlings in vegetable beds.

On the downside, if you haven’t weeded your winter garden yet, and the weeds have gone to seed, spring rain could mean a bumper summer crop of crabgrass.

So, what to do, apart from moving fast to weed while the soil is soft, and then promptly mulching? Master Gardener coordinator Yvonne Savio advises betting on every conceivable weather pattern in late spring and early summer, then enjoying the fruits of whatever ultimately happens.

First, she says, wager that cool weather will continue. Put in more fast-growing spring crops such as lettuce. But also bet on a hot summer and, be they from seed or seedling pack, get your summer crops of cucumbers, runner beans, tomatoes, squash and corn in the ground. Both bets may not pay out. A heat wave might make your wager on a prolonged spring a bust. Your late lettuce may wilt, or bolt, or grow tough and bitter.

“But what have you lost?” Savio asks. “Some seeds.” If you win, you’ll be in salad throughout June.

For help assessing the odds of a cool summer as opposed to a hot one, and an early summer as opposed to late one, I contacted Jet Propulsion Laboratory oceanographer Bill Patzert. Some of you may remember that in September he put 80% to 90% odds on a strong cooling of equatorial waters in the Pacific, a system known as La Niña, producing winter drought for Southern California.

After nearly record rains in December, and a Christmas dinner of crow instead of turkey, he knew that Southern California ended up on the lucky side of La Niña’s traditional cutoff somewhere between San Diego and the Oregon border. This system tends to drive rain north and keep the south dry, but we were doused and poor Texas was parched.

Bloodied but unbowed, Patzert is again willing to read ocean currents and hazard some odds for our summer.

“Usually the summer in Southern California goes as the ocean temperatures off the West Coast dictate," he says. An ocean temperature "anomalies" map indicates water is unusually cool (blue). "That would make it a cooler-than-normal summer because we'll get more marine layer. But we always get that rogue week or two of heat wave.”

As if sensing a prolonged opportunity to plant, the Common Ground Victory Garden Initiative classes extend through June. However, Savio does not recommend planting in July or August, during which time we should be busy harvesting what we’ve sown.

Come fall, when summer crops are done, the woman named horticulturist of the year by the Southern California Horticultural Society once again recommends playing the odds. Don't just plan for cool-season crops such lettuce, cilantro, kale, beets and radishes, Savio says, but also try another round of hot-season vegetables such as squash in the event of an Indian summer. “You never know what the weather will be,” she says.

So, to recap uncertain advice in an uncertain world, we have May showers from nature, a prediction of a cool summer from a scientist, advice to plant for all eventualities from a master gardener, and exhortations to get out and weed and mulch from me.

-- Emily Green

Green's column on low-water gardening usually appears here on Fridays. For an easy way to follow future installments, join our Facebook page dedicated to gardening in the West.